EN ISO 16634-1:2008

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Reagents
6 Apparatus
7 Sampling
8 Preparation of test sample
9 Procedure
   9.1 General
   9.2 Test portion
   9.3 Control of oxygen demand
   9.4 Calibration
   9.5 Determination
   9.6 Detection and integration
10 Calculation and expression of results
   10.1 Calculation
        10.1.1 Nitrogen content
        10.1.2 Crude protein content
   10.2 Expression of results
11 Precision
   11.1 Interlaboratory tests
   11.2 Repeatability
   11.3 Reproducibility
12 Test report
Annex A (informative) - Flowchart for the basic design of
        a Dumas apparatus
Annex B (informative) - Schemes of suitable types of
        Dumas apparatus
Annex C (informative) - Equipment calibration
Annex D (informative) - Examples of factors for converting
        nitrogen content to protein content
Annex E (informative) - Result of collaborative studies
Annex F (informative) - Relationship between Dumas nitrogen
        and Kjeldahl nitrogen
Bibliography

ISO 16634-1:2008 specifies a method for the determination of the total nitrogen content and the calculation of crude protein content of oilseeds and animal feeding stuffs.This method, like the Kjeldahl method, does not distinguish between protein nitrogen and non-protein nitrogen. For the calculation of protein content, various conversion factors are used.This method is not applicable to milk and milk products.